Nano- and microstructuring of solids by swift heavy ions

Abstract

We review the current stage of research of track formation processes and mechanisms in materials irradiated by swift ions. We show that the nature and morphology of tracks depend on the type and structure of the material and on the energy density transfer to its electron subsystem. Swift heavy ions serve as tools to synthesize nanoclusters and nanowires, to controllably change their morphology, and to tailor electronic, magnetic, and optical properties. The unique optical, photoelectric, and conducting properties of tracks can be used to create a new generation of electronic and optoelectronic nanosize devices. These low-dimensional objects exhibit quantum behavior and are stimulating a broad range of fundamental and applied research.

Dependence of track etching kinetics on chemical reactivity around the ion path

“…Being decelerated in solids, swift heavy ions (SHI) with masses M > 10 a.m.u., and energies E > 1 MeV/a.m.u. considerably excite the electron subsystem of a target (>95% of the total ion energy loss, dE / dx = S e = 5–50 keV/nm 1–3 ) along their trajectories. Relaxation of this excitation results in structure transformations in the nanometric vicinity of the ion path 1–8 .…”

“…considerably excite the electron subsystem of a target (>95% of the total ion energy loss, dE / dx = S e = 5–50 keV/nm 1–3 ) along their trajectories. Relaxation of this excitation results in structure transformations in the nanometric vicinity of the ion path 1–8 . Changes in electronic and chemical properties of a target can appear at distances up to hundreds of nanometers from the track axis 9–12 .…”

Fundamental Phenomena and Applications of Swift Heavy Ion Irradiations

“…Destabilization of the atomic lattice is a result of electronic excitation and may take place around the SHI trajectory due to: (i) increase of the kinetic energy of atoms due to elastic scattering of atoms with electrons from ionization eventsfinally leading to thermal melting [108], (ii) severe modification of the interatomic potential due to electronic excitations and resulting in breaking of chemical bondsinducing non-thermal melting [109,110], (iii) change of atomic charge states leading to Coulomb repulsion between neighboring ionized target atomscalled Coulomb explosion [111], and (iv) defect accumulation under prolonged beam exposure in the case when an individual ion impact is insufficient to cause damage [112]. The relative importance of these processes for track formation is still debated, with the currently prevalent opinion that the thermal melting (i) plays the dominant role [113]. It is based on the notion that Coulomb explosion (iii) is only important for finite size systems such as nanoclusters or molecules, or near the sample surface.…”

Express Method of Estimation of Etched Ion Track Parameters in Silicon Dioxide Template

“…Recently there has been a great interest in various types of nanoscale objects that have new interesting properties . Depending on the intended applications, nanostructures with different functional properties are required, which are predetermined by composition and morphology.…”

“…Recently there has been a great interest in various types of nanoscale objects that have new interesting properties. [1][2][3][4][5][6] Depending on the intended applications, nanostructures with different functional properties are required, which are predetermined by composition and morphology. It is possible to vary the composition of the nanostructures by selecting precursors, and the morphology is the most easily controlled by using porous matrices or as they are also called "templates."…”